This invention relates to a plastic cartridge made of a synthetic resin which is provided with a case member made of a synthetic resin and having an open end accommodating a propellant charge and an igniter charge for igniting the propellant charge upon the exertion of pressure on the igniter charge, and with a lid or cover made of a synthetic resin for sealing the open end of the case member. The invention furthermore concerns a cartridge belt magazine made of a synthetic resin with a case member strip made of a synthetic resin having several case members which are connected together, and with a sealing lid strip made of a synthetic resin having several joined-together sealing lid sections for closing off the case members.
Such (propellant) cartridges of plastic are utilized in firing devices, especially stud drivers of a great variety of types. In these devices, the cartridges are, in most cases, integrated into magazine strips (i.e. cartridge belt magazine). However, plastic cartridges can also be utilized in center-fired weapons. The advantages of plastic cartridges reside, in particular, in the relatively low costs for material and manufacture; for example, the cartridges can be produced by an injection-molding technique. A plastic cartridge and a plastic cartridge belt magazine of the type, heretofore described are known from EP 377,924 A1.
A certain problem in plastic cartridges consists in the initiation of the igniter charge by a striker. This is due, on the one hand, to the plasticity of the synthetic resin material damping the striker energy; for which reason the impulse with which the striker hits the lid or the case member must be enhanced. Secondly, the initiation of the igniter charge poses difficulties in plastic cartridges since the igniter charge is disposed between two layers of synthetic resin material. The deformation energy produced by the striker yields, under such conditions, an adequate temperature increase in the igniter charge only if the compression (force/surface area) and/or the deformation under this compression in the igniter charge is far higher than permitted by the synthetic resin. Sufficient compressions of the igniter charge can be realized only in case the igniter charge is accommodated between two metal parts, as is the case in metallic cartridges. Based on their material characteristics, igniter charges cannot be brought to any desired deformability (force/path). On account of the herein described properties of thermoplastic synthetic resins, in particular, the use of plastic cartridges in place of metallic cartridges in the stud drivers or center-fired weapons designed for metallic cartridges is not readily possible.